Influence of long-term exposure of high-density direct current on the current carrying ability of 2G HTSC tapes based on the REBCO

In this work, the phenomena of electromigration in samples of HTSC tapes of the 2nd generation was investigated. Samples of REBa₂Cu₃O_7-x (REBCO, where RE is a rare earth element) were used in the form of a copper-plated tape. A superconducting bridge was preliminarily formed on the surface of the tape by the method of chemical etching (to decrease the total value of critical current). The sample was exposed by a direct current of I = 0.9I_c. The duration of exposure was up to 350 hours. The value of the current density in the area of the bridge was J = 1.38×10¹⁰A/m². The measurements were carried out at liquid nitrogen temperature (77 K). The influence of the electric current flow on the value of the sample critical current is controlled at the selected time intervals. The experiment showed high stability of the tape under the specified conditions. (paper)